This invention relates to a method of measuring the efficiency of permanent waving applied to human hair and relates also to a method and apparatus used for the diagnosis of the quality of hair on the basis of the result of measurement of the waving efficiency.
The experience and sense of a beauty artist are presently chiefly relied upon for the selction of the waving lotion, determination of the size of the waving rod, determination of the processing time, etc. in applying permanent waving to the hair.
Since, thus, the factors to be definitely determined while primarily taking into account the quality of hair and the desire of a customer are decided on the basis of the experience and sense of a beauty artist, customers have frequently been dissatisfied with the finish, and there have been such cases in which a slight error of the artist's judgment leads to a great trouble.
Such a situation has occurred because there have been no methods and apparatus capable of simply measuring the hair waving efficiency thereby diagnosing the quality of hair. The factor required for the diagnosis of the hair quality is to find out whether permanent waving is easily or difficulty applicable to hair of a customer. For this purpose, permanent waving should be actually applied to the hair of the customer, and the efficiency of permanent waving should be measured.
Various methods of waving efficiency measurement have heretofore been attempted for the principal purpose of evaluating the effect of a waving lotion. Basically, the steps include winding a swatch of hair around a glass rod, applying permanent waving to the hair swatch, removing the hair swatch from the glass rod and examining the resultant shape of the hair swatch. According to such a method, however, the permanent-waved hair swatch becomes three-dimensional, and digitization of the resultant shape for the purpose of accurate evaluation is considerably difficult.
According to a report of Donald H. Kirby in Drug Cosmet. Ind. 80,314 (1957), permanent waving is applied to a swatch of hair in zigzag form, and the waving efficiency is evaluated from the length of the resultant wave having a planar spread. On the other hand, according to a report of Kondo in T. G. Report No. 35 (1959) referring to the method disclosed by John W. Haefele in U.S. Pat. No. 2,615,828, a swatch of hair is wound around a glass rod, and, after application of permanent waving to the hair swatch, the hair swatch is cut on the rod for evaluating the waving efficiency by measuring the diameter of the curl.
The Kirby's method (and its improved method) is now widely employed in this field. However, both of the Kirby's method and the Haefele's method are not reliable in the reproducibility of results and are defective in that the artist's skill is required and numerous measurements must be repeated to enhance the reliability. That is, these methods are not suitable for the judgment of the hair waving efficiency within a short length of time.